The field of the present invention relates generally to measurement probes, and more specifically, to a method of integrating a multimodal measurement probe for use in measuring a machine component and a system for inspection comprising such an integrated probe.
Prior to being placed in service, at least some known rotor blades or other components having an internal geometry or having narrow openings are measured using measurement probes to ensure that that the blade has the proper dimensions for use in a turbine engine. Often, such blades are inspected via a non-destructive inspection technique to ensure that each blade does not include internal/external defects and/or cracks that may not be visible to the naked eye. Generally, it is important to measure both the external and internal geometry and structure of the blade. A coordinate measuring machine can only conduct external geometry measurements and can not inspect wall thickness and any internal structure/defects of a part.
Coordinate measuring machines (CMMs) have been used for external dimensional measurement. Nondestructive examination (NDE) sensors including ultrasound (UT) sensors, eddy current (EC) sensors, etc., have been used separately to determine a thickness, internal defects, or surface condition measurements without being linked to the three-dimensional geometry of the component under inspection.
Known methods for measuring a blade generally require several separate processes to inspect both the internal and external geometry of the blade. In one process, at least some known blades are inspected using computed tomography (CT) and/or ultrasonic (UT) to inspect the internal geometry of the blade. A coordinate measuring device, such as a coordinate measuring machine (CMM) probe or a laser scanner on a CMM, is separately used to inspect the external geometry of the blade. Accordingly, a significant amount of time may be required to complete the setup and inspection process for each individual process of CT, CMM, and/or UT. Moreover, UT inspection currently requires a motion control system and, therefore, requires a pre-inspection process to program the motion control system to accurately follow the contour of the blade.
Accordingly, such known inspection methods are generally time-consuming, not suitable for in-situ inspection, and/or expensive. Further, for CMM, complicated blade geometry, such as a component having a deep, narrow opening or cavity, generally requires complicated setups and/or bending of the CMM probes to measure the cavity geometry. Moreover, for a compressor blade, the CMM probe must travel across both the pressure and suction sides of the blade. In addition, the CMM probe must compensate for the curvature deviation from CAD models. However, probe compensation is generally a computationally complicated process. Meanwhile, the CMM touch probe requires a detailed CAD model to conduct dimensional measurement, which might not be available all the time. Moreover, different sensors have different strengths. For example, a CMM touch probe has a higher accuracy, even on small features, but is generally slow, while a laser probe or a proximity sensor is non-contact and can measure quickly, but typically with a much lower accuracy. Similarly, a UT sensor can detect deep cracks, while an EC sensor can identify fine/shallow surface cracks. Moreover, infrared (IR) is good for measuring thin walls with a high speed, while an X-ray CT can provide a thicker-wall-thickness measurement. However, the defects and real geometry of a part are usually unknown prior to inspection. An intelligent probe should be able to conduct adaptive inspection at real-time, based on the real-time measurement data from sensors, and to optimize the usage of sensors based on the real geometry and defect types obtained on the fly.